使用Socket.io的问题

Question

I am trying to use socket.io for the first time, Im using it with a MEAN Stack. I have set it up the following way.

Server.js

var express  = require('express');
var app      = express();                               // create our app w/ express
var server = require('http').createServer(app);
var io = require('socket.io')(server);

app.listen(port);

io.on('connection', function(socket) {

    socket.emit('message', {
        'message': 'hello world'
    });
});

HTML File

<script>
var socket = io.connect();

socket.on('message', function(data) {
    console.log(data.message);
});
</script>

I couldn't find the socket.io.js file so I searched for a CDN for the script. I used the following.

<script src="https://cdnjs.cloudflare.com/ajax/libs/socket.io/1.4.6/socket.io.js"></script>

I tried downloading the socket.io.js from their website but the website seems to be down. I can access it, I get the 502 BAD GATEWAY error ( http://socket.io )

When I load my HTML page after setting everything up as shown above I get the following error in the console.

Any help will be greatly appreciated!

UPDATE:

Answer 1

The socket.io server will perform some magic to provide that file when you retrieve it like this:

<script src="/socket.io/socket.io.js"></script>

EDIT : ah, I see the problem: your Express setup is incorrect.

var express = require('express');
var app     = express();
var server  = require('http').createServer(app);
var io      = require('socket.io')(server);

app.listen(port);

You're attaching socket.io to a server created by http.createServer , but with app.listen() you're actually creating a new server, one that socket.io isn't attached to.

You can make the setup a bit simpler:

var express = require('express');
var app     = express();
var server  = app.listen(port);
var io      = require('socket.io')(server);

No need to use http .

Answer 2

As of now, socket.io website is still down. If you don't have the file in your server, it does not help using /socket.io/ because this points to a route on your server and that route doesn't seem to exist on your app. With this config, you need to be serving the .js file statically from your server - but I don't see that on your server code.

When you try the CDN, make sure the file is being loaded.